Refrigerating apparatus



March 13, 1962 J. w. JACOBS 3,024,963

REFRIGERATING APPARATUS Original Filed March 23, 1955 2 Sheets-Sheet l INVENTOR. James' W. Jacobs His Attorney March 13, 1962 J. w. JACOBS REFRIGERATING APPARATUS 2 Sheets-Sheet 2 Original Filed March 23, 1955 v mi INVENTOR.

W. Jacobs James His Attorney United States Patent 3,024,963 REFRllGERATING APPARATUS James W. Jacobs, Dayton, Ohio, assignor to General Motors Corporation, Detroit, Mich., a corporation of Delaware Original application Mar. 23, 1955, Ser. No. 496,131, now Patent No. 2,907,426, dated Oct. 6, 1959. Divided and this application May 2, 1953, Ser. No. 732,580 3 Claims. (Cl. 230-15) This invention relates to refrigerating apparatus, and more particularly to a compressor construction.

This application is a division of my copending application S.N. 496,131 filed March 23, 1955, in which the clutch mechanism is claimed per se.

In designing refrigerant compressors for use in automobile air conditioning, it is important to conserve on space, cost, and weight without sacrificing strength and efficiency. It is an object of this invention to so construct and arrange the parts of a compressor that it is possible to support the compressor pulley and parts of a clutch directly on the compressor shaft without causing undue strain on the shaft.

Another object of this invention is to provide a compressor wherein the compressor head clearance can. be adjusted in a simple and practical manner.

It is another object of this invention to provide an axial compressor for use with a magnetic clutch carried by the compressor housing wherein it is possible to adjust the clutch air gap clearance without disturbing the compressor head clearance adjustment.

Further objects and advantages of the present invention will be apparent from the following description, reference being had to the accompanying drawings, wherein a preferred form of the present invention is clearly shown.

In the drawings:

FIGURE 1 is a vertical sectional view taken substantially on line 11 of FIGURE 3, showing a preferred embodiment of the invention;

FIGURE 2 is a sectional view taken substantially on the line 2-2 of FIGURE 1 and looking in the direction of the arrows;

FIGURE 3 is a sectional view taken substantially on line 3-3 of FIGURE 1; and

FIGURE 4 is a sectional view taken substantially on line 4-4 of FIGURE 1.

Referring now to the drawing wherein a preferred embodiment of the invention has been shown, reference numeral designates a cylindrical sheet metal compressor casing which is closed at its one end by a cast cylinder block and bearing supporting element 12 and is closed at its other end by a casting 14 which houses the main shaft bearing 24 and the clutch operating solenoid coil 40. The casting 14 is brazed or otherwise secured to the casing 10. The main compressor drive shaft 16 is supported at its inner end within the cylinder block '12 by means of a needle bearing assembly 20 which allow longitudinal movement of the shaft relative to the cylinder block for a purpose to be described more fully hereinafter. The shaft 16 is supported adjacent its outer end by means of a ball bearing assembly which includes an inner ball race 22 keyed to the shaft 16 so as to prevent endwise movement of the shaft relative to the bearing assembly. The ball bearing assembly includes an outer ball race 24 which is keyed to the casting 14 whereby the drive shaft 16 is prevented from having any endwise movement relative to the casting 14.

The free end of the drive shaft 16 serves to support a drive pulley assembly generally designated by the reference numeral 26. This assembly includes a pulley element 28 which is supported for free rotation relative to the shaft by means of a ball bearing assembly 30. As

ice

indicated in FIGURE 1 of the drawing, the inner race of the ball bearing assembly is fixed to the drive shaft 16 and the outer race is fixed to the pulley 28. A first clutch disc 32 is splined to the shaft 16 so as to at all times rotate in unison with the shaft 16 and a second clutch plate 34 is rotatably mounted on the hub portion of the first clutch plate 32 as shown. The clutch plates are provided with the usual friction surfaces 36 for engaging complementary friction surfaces provided on the pulley assembly 26. The clutch is of the type more fully shown and described in my copending application S.N. 418,931 filed March 26, 1954, now Patent No. 2,866,- 528, to which reference is hereby made for a more complete description of the construction and operation of the clutch. The clutch includes the usual relative rotation reaction spreader ball means 38 which serve to cam the discs 32 and 34 into clutching engagement with the clutch surfaces 36 in response to energization of the solenoid coil 40 which is imbedded within the main casting 14 as shown.

The spreader ball means shown in my earlier filed application were steel ball bearings whereas I have that steel ball bearings are very hard on the spreader plates and eventually cause failure of the clutch. For one thing the centrifugal force acting on the metal balls caused the balls to distort the shape of the ball socket 39 after prolonged use. To overcome these problems and to reduce the severity of the impact on the clutch parts, the balls are made of plastic such as nylon which is a polyamide material which is a reaction product of a polybasic acid such as adipic acid with a diarnine such as hexamethylene diarnine. The nylon material has resistance to permanent deformation and requires no fluid or grease like lubricant which might travel by centrifugal force outwardly onto the clutch. surfaces. The spreader balls could have a solid type lubricant such as graphite or molybdenum disulfide incorporated as a filler in the plastic composition. Nylon balls having a Rockwell hardness of approximately R118 have been found to be very satisfactory and to have the necessary toughness to resist fracture or crushing. The nylon is a thermoplastic material which can withstand normal temperatures without undue softening or loss of strength, but it has a relatively sharp melting point whereby the balls serve as protective devices which melt at excessive temperatures such as would be encountered if for any reason the clutch became greatly overloaded and began slipping and thereby generating heat. When using clutches having metal spreader balls, the continued. slipping of the clutch in the combination shown would not only generate enough heat to ruin the friction material at the clutch surfaces but would also generate enough heat so that some of the heat generated would be conducted to the compressor shaft, the shaft seal and other parts which would be damaged by excessive heat. In the structure shown herein the nylon balls are closest to the friction surfaces of the clutch so that in the event of clutch slippage the heat generated thereby would melt the balls and declutch the clutch before much of the heat would reach the vital parts of the compressor.

The clutch plate 34 is provided with an armature 42 which is attracted by the solenoid 40 whenever the solenoid is energized so as to cause the friction surface 36 on the plate 3-4 to engage the complementary friction surface on the pulley 28 and thereby initiate the necessary relative rotation between the clutch plate 32 and 34 so as to cause the spreader balls 38 to firmly hold the clutch surfaces in engagement in accordance with well known practice. Upon deenergization of the solenoid 40, the spring washer 44 will assist in disengaging the clutch so as to stop operation of the compressor even though the pulley 28 continues to rotate.

It will be observed that the main shaft bearing including the ball races 22 and 24 are arranged radially inwardly of the armature coil 40 with the result that the bearing for the main drive shaft may be placed very close to the end of the drive shaft 16. This construction has the advantage that it reduces the size of the assembly and also eliminates the need for a long overhang on the compressor shaft which must support the weight of the relatively heavy drive pulley and some of the clutch parts. The casting 14 serves to house the usual shaft seal assembly 50 and oil pump 52. The compressor is of the axial type which includes a wobble plate 54 mounted on the offset crank portion 56 which is keyed to the shaft 16 as shown. The cylinder element 12 is provided with a plurality of spaced cylinder bores 60 in which piston elements 62 are caused to reciprocate by means of connecting rods 66 operated by the wobble plate 54 in accordance with well known practice. The wobble plate is prevented from rotating by means of the guide shoe 65 which operates within the usual guides 67 formed integrally with the casting 12.

The usual cylinder head assembly generally designated by the reference character 70' is bolted to the casing by means of the cap screws 72. In order to provide the necessary clearance between the pistons and the valve plate 74 there is provision for introducing shims 76 between the ends of the casing 10, and the shoulder 78 provided on the cylinder casting 12. Since the construction of the wobble plate and the inlet and outlet ports are of conventional design, it is not believed necessary to describe these in greater detail.

While the form of embodiment of the invention as herein disclosed constitutes a preferred form, it is to be understood that other forms might be adopted, as may come within the scope of the claims which follows.

What is claimed is as follows:

1. In combination, a tubular sheet metal casing, a cylinder block secured within one end of said casing and having a plurality of cylinder bores formed therein, a

bearing block secured within the other end of said casing, a drive shaft, a first bearing carried by said bearing. block for supporting one end of said drive shaft, a shaft seal assembly supported in said bearing block and restricting the escape of fluid along said shaft, a compressor drive pulley on said shaft, a clutch having one clutch element on said shaft and having a complementary clutch element on said pulley, a stationary clutch operating solenoid in said bearing block, said first bearing being disposed between said seal and said clutch, a bearing provided in said cylinder block for supporting the other end of said drive shaft, complementary elements on said shaft and said bearing block preventing axial movement of said shaft relative to said bearing block, pistons operable Within the bores in said cylinder block, a wobble plate assembly carried by said shaft and transmitting power from said drive shaft to said pistons, and a shim between said cylinder block and said casing for adjusting the relative location of said cylinder block to said casing without disturbing the position of said shaft relative to said bearing block.

2. In a compressor assembly, a tubular sheet metal casing, a cylinder block secured within one end of said casing and having a plurality of cylinder bores formed therein, a one piece clutch solenoid housing and bearing block secured within the other end of said casing, a drive shaft, a first bearing carried by said bearingblock supporting one end of said drive shaft, a second bearing provided in said cylinder block supporting the other end of said drive shaft, complementary elements on said shaft and said bearing block preventing axial movement of said shaft relative to said bearing block, pistons operable Within the bores in said cylinder block, a wobble plate assembly carried by said shaft and transmitting power from said drive shaft to said pistons, and a shim between said cylinder block and said casing for establishing the desired relative location of said cylinder block to said casing without disturbing the piston of said shaft relative to said bearing block, said block having a pair of concentric recesses surrounding said shaft, a clutch mounted on the outer end of said shaft, a clutch operating solenoid in one of said recesses, and shaft seal means within the other of said recess for preventing the escape of fluid between said shaft and said block, said first bearing being disposed between said shaft seal and said clutch so as to prevent fluid escaping from said shaft from being thrown onto said clutch.

3. In a combination compressor and clutch assembly, a sheet metal casing, a cylinder block secured within one end of said casing and having a plurality of cylinder bores formed therein, a bearing block secured to the other end of said casing, a drive shaft, a first bearing carried by said bearing block for supporting one end of said drive shaft, a shaft seal assembly supported in said bearing block and restricting the escape of fluid along said shaft, a second bearing in said cylinder block for supporting the other end of said drive shaft, complementary end thrust bearings on said shaft and said cylinder block preventing axial movement of said shaft relative to said bearing block, said first bearing being disposed between said seal and said clutch, pistons operable within said cylinder bores, a wobble plate assembly carried by said shaft and transmitting power from said drive shaft to said pistons, a drive pulley rotatably supported on said drive shaft in close proximity to said bearing block, a clutch having a first clutch element carried by said shaft and having a second clutch element secured to said pulley for drivingly connecting said pulley to said shaft, said clutch including a clutch operating solenoid disposed within said bearing block, said solenoid being spaced radially outwardly from said first bearing carried by said bearing block, the one end face of said bearing block having a circular groove formed therein for receiving said solenoid.

References Cited in the file of this patent UNITED STATES PATENTS 2,037,961 Boden Apr. 21, 1936 2,106,385 Springer Jan. 25, 1938 2,664,981 DOzouville Jan. 5, 1954 2,798,663 Chayne et al July 9, 1957 2,807,148 Jacobs Sept. 24, 1957 2,866,528 Jacobs Dec. 30, 1958 FOREIGN PATENTS 1,064,506 France May 14, 1954 

